The present disclosure relates to a liquid crystal display device and to a liquid crystal display that includes the liquid crystal display device.
In recent years, as high resolution, downsizing, and high luminance of a projection display have been accelerated, as a display device thereof, a reflective device in which its downsizing and its high resolution are obtainable and its light use efficiency is promising has attracted attention and has come into practical use. As the reflective device, an active-type reflective liquid crystal display device in which liquid crystal is injected into a space between a pair of substrates placed oppositely is known. In this case, a transparent electrode substrate in which a transparent electrode is laminated on a glass substrate is used as one of the pair of substrates, and a drive device substrate using a silicon (Si) substrate configured of, for example, a CMOS (complementary-metal oxide semiconductor)-type semiconductor circuit is used as the other one of the pair of substrates. On the drive device substrate, a metal reflective pixel electrode for reflecting light and applying a voltage to the liquid crystal is arranged, and thereby a pixel electrode substrate is formed as a whole. The reflective pixel electrode is made of a metal material containing aluminum as a main component that is typically used in LSI (large scale integrated) process.
In such a reflective liquid crystal display device, by applying a voltage to the transparent electrode provided on the transparent electrode substrate and to the reflective pixel electrode provided on the drive device substrate, the voltage is applied to the liquid crystal. At this time, the optical characteristics of the liquid crystal are changed according to an electric potential difference between the foregoing electrodes, and incident light is modulated. By such modulation, gradation expression is enabled, and an image is displayed. Of the reflective liquid crystal display devices, in particular, the active-type reflective liquid crystal display device in which perpendicularly-aligned liquid crystal is injected has high contrast and high response speed, and therefore the active-type reflective liquid crystal display device has attracted attention as a projection device in recent years (for example, see Japanese Patent Publication No. 4386066).